Electromagnetic device



Dec. 7 1926. 1,610,064

W. L. MERRXLL ELECTROMAGNETIC DEVICE Filed Dec. 15, 1921 Inventor 1 Wilbur- L. Merrill,

His Attorney.

Patented Dec. 7, 1926.

UNITED STATES 1 1,610,064 TENT- o-FFrc-e.

wILBUR L; MERRILL, or scHnNEo'r nY, NEW YORK. ASSIGNORVY T0 GENERAL ELEC- TRIC COMPANY, A CORPORATION on NEW YORK.

ELEcrRoMAGNE-rrc DEVICE.

Application filed December 13, 1921.

My invention relates to improvements in electromagnetic devices, as for example electron'iagnetic switches; and has for its object the provision of means for preventing the vibration of the movable magnetic member oi the electromagnetic device and the vibra tion'ot the switch member connected thereto in case theelectromagnetic device is an electric switch.

My invention relates more specifically to improvements in electromagnetic devices for alternating current circuits. In certain types of electromagnetic switches, as, for instance, those in which the switch member is biased to an operative position by gravity or otherwise and is moved out of contact when acertain de ree of energization of the winding is reache c l some difficulty has been experienced due to th'e vibration or the contact. I In switches of this character the winding isordina-rily energized constantly and the switch member moves up or down to either open or closethe circuit depending upon the degree of energization of the winding. Ithas been found that under certain conditions as, for instance, where the frequency gets somewhat below that for which the switch was designed, there is, a

) tendency torthe, contactto tollowthe line frequencyand vibrate, therebyat times causing destructive arcing at the contacts. In Gums-weeds, aswitch, which at cycles would have littleor no tendency to vibrate, at 15 cycles might vibrate badly. This is because the core or magnetic movable member could not be accelerated in a sixtieth 01 a second 'wl'iereas it"might be accelerated in a fifteenth of a second and iollow the line he quency. In carrying out invention I give to the switch member or to the magnetic movable member, connected to the switch member, or to the: magnetic movable member and the switch member connected thereto, a certain amount of inertia without adding to the effective weight of the magnetic movable member and the switch member connected thereto which must be. moved in response to the energization of the winding. This I accomplish in one form of my inventionby applying to the magnetic nrovable member a weight which is balanced in someway as, for instance, by another weight so that the net weight of the'parts to be acted upon bythe winding is not increased. Other objects and purposes of my invention Serial no. 522,149.

the lower end of the core is a contact disk 12 cooperating with stationary contacts 13. The winding 10, when energized to a certain value, will lift the contact disk 12 out'of engagement with the contacts 13 and when certain valuethe weight of the parts will carry the disk 12 into engagement with the contacts 13. This, of course, is a well-known form of switch and needs no further descrip tion. I

If the winding 10 were energized by alternating current the moving parts of the switch would be designed so that they would notvibrate on say, tor-instance, a (it) cycle circuit. At this freqti'ency the parts ot'a switch of this character could not be ac celerated in the time necessary to set the parts vibrating with the freqdcncy. If, however, the frequency should drop to a considerably lower value say, for instance, to 15 cycles such a vibration. min-ht readily be set up and cause arcing on the contacts 13, as well as an objectionable humming sound. In order to overcome these objections I have devised means whereby the inertia Oftllfl parts is increased so that even at a" lower frequency the parts could not be accelerated. This I accomplish. in the form. shown in the drawing by means of two weights 14 and 15, which are arranged so as to counter-balance each other in their effect upon the core 11 and. the switch parts.

The weight 1 1 is mounted upon one end of a rod 16. pivoted at 17, the opposite end of the rod being pivoted to the rod 18 upon which this contact 12 and thc core 11 are mounted. \Veight 15 is mounted at the mid die portion of a rod .19 pivoted at one end at 2.0,v and the opposite. end of the rod being pivoted to the rod 18. The pivotal connections oi' these two arms 16 and 19 to' rod 18 are slotted as shown and the weightsyls and 15 are adjustably l'l'lOUIltUl upon the rods. The weight 11 will obviously have a tenthe energization oi the winding drops to a till dency to force the switch parts upward whereas the weight 15 will have the opposite tendency; namely, to force the switch parts downward. -Assume for the sake of simplicity that the weight 15 weighs twice as much as weight 14; say, for instance, the weight let weighing 5 ounces and weight 15, ounces, the leverage of weight 14 being 1:1, the weight 14; will exert an upward pull on the witch parts equal to 5 ounces wherethe weight 15, being midway of rod 19, will exert a downward tendency equal to 5 ounces. The two weights, therefore, balance each other so far as concerns their effect upon the weight of the core 11 and the other movable switch parts and the degree of energization of the operating winding 10 necessary to operate the magnetic member 11 is not altered. It is obvious however that the inertia of the core and the switch con tact 12 hasbeen greatly increased and that with this increased inertia the core and the switch contact could not be accelerated even at a very low frequency. I have found that by properly adjusting the weights and leverage a magnetic device of this character would be substantially free of vibration at the lowest frequencies which obtain in practice. It will be seen, therefore, that I have provided means whereby the inertia of the parts is greatly increased without substair tially affecting the weight which must be moved. In other words, there is substantially no more pressure upon the contacts 13 than without the weights; in fact, therev may be a littleless due to the friction in the parts.

While I have described my invention as embodied in concrete form and as operating in a specific manner in accordance with the I provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is set forth in the annexed claims.

Y /hat I claim as new and desire to secure by Letters Patent of the United States, is

1. An electromagnetic device for alternating current circuits, comprising a magnetizing winding, a magnetic movable member under the control of said winding, and means comprising a balanced movable mass for increasing the inertia of the said memher to prevent vibration due to the alternations of the n'iagnetizing current of said winding without substantially increasing the degree of energization of the winding necessary to move the said magnetic member.

2. An electromagnetic device for alternating current circuits, comprising a magnetizing winding, a magnetic movable memher under the control of said winding, and means comprising a balanced movable mass connected to the said member for imparting thereto a relatively high inertia to prevent vibration due to the alternations of the magnetizing current of said winding without substantially increasing the degree of energization of the winding necessary to move the said magnetic member.

:3. An electron'lagnetic device for alternating current circuits comprising a mag netizing winding, a magnetic movable memher under the control of said winding, and an independently supported movable mass connected to said member for preventing vibration of the member due to the alternations of magnetizing current of said winding without substantially increasing the degree of energization of the winding necessary to move the said magnetic mem ber.

An electromagnetic device for alternating current circuits comprising a magetizing winding, a magnetic member oper able between two positions responsively to a predetermined variation in the magnetizing current of said winding, and a balanced movable mass pivotally supported independently of said magnetic member and connected thereto for preventing vibration thereof due to the alternations of the magnetizing current of said winding without substantially changing the variation in the magnetizing current of the winding necessary to operate said magnetic member.

5. An electromagnetic device for alternating current circuits, comprising a magnetizing winding, a magnetic movable member under the control of said winding, and a plurality of pivotally mounted weights connected to and balanced with respect to the said member for increasing the inertia of said member to prevent vibration due to the alternations of the magnetizing current of said winding.

6. An electromagnetic switch for alternating current circuits, comprising a magnetizing winding, a magnetic movable member controlled thereby, a switch member normally in operative position which assumes either an operative or an inoperative position with varying degrees of energization of the winding, the said switch member connected to the said magnetic member to'be operated thereby, and means comprising a balanced movable mass for preventing the said magnetic member and the said switch member from vibrating due to alternations of the magnetizing circuit.

7. An electromagnetic switch for alternating current circuits, comprising a magnetizing winding, a switch member normally in operative position which assumes either an operative or inoperative position with varying degrees of energization of said winding, and means for increasing the inertia of the switch member to prevent vibra- Ill) tion due to the alternations of the magnetizing circuit without substantially increasing the degree of energization necessary to move it.

8. An electromagnetic switch for alternating current circuits, comprising a mag-- netizing winding, a switch member having a bias towards an operative position and movable into and out of said position upon varying degrees of energization of said winding, and means for increasing the inertia ofsaid switch member without affecting the bias thereof.

9. An electroniagnetic device for alternating current circuits, comprising a magnetizing winding, a magnetic movable member operated thereby to various positions depending upon the degree of energization of said winding, a weight associated with said member to be accelerated upon movement of the member, and means for counterbalancing said weight whereby vibration of the member due to alternations in the magnetic circuit are prevented. I

10. An electromagnetic switch for alternating current circuits comprising a magnetizing winding, a switch member oper ated thereby to various'positions depending upon the degree of energization of said Winding and balanced weights associated with said member for preventing vibration of the member due to alternations in the magnetizing circuit.

In Witness whereof, I have hereunto set my hand tiis 12th day of December, 1921.

\VILBUR L. MERRILL. 

